Pulping machine



Patented Jan. 24, 1928.

UNITED STATES IALLICXH, 0F D'UBEN, GERMANY.

mme Meermin.

Application med lay 17, 1987, Serial No. 191,960, and in Germany lime 81, 1828.

This inventionv relates to pulping machines for paper mills. It is well known that the amount of material that is reduced to pulp by a ulping machine increases with the wldth o? the rotary pulping cylinder. For this reason attempts have been made to increase the output of pulping machines, havin a container or tank with two pulp channe s or races, by increasing the width of the cylinder. which usually amounted to only 0.8 of its diameterA was increased up to 1.2 of its diameter. But the desired effect could not result by thus increasing the width ofthe cylinder, because as this width, and width of the pulp race that depends thereon, increases, the distance of travel of the pulp at the outer edge of the race is also lengthened. Consequently the degree of slope or inclination of the bottom o the race at its outer edge becomes so small that the pulp stagnates thereat, or flows much slower than the pulp at the inner edge or Wall of the race, so that the outer portion ot the grinding cylinder or cutter cylinder has but little effect. The crosswise mixing of the pulp, when its consistency where it is led in is thick, is unsatisfactory in consequence ot the large width of the cylinder and ulp race of such machines, and a draw ack which results therefrom is that the pulp that circulates quickly at the short middle wall of the race is unduly shortened and squashed., While the fibres that pass along the long outer wall of the race are ground insufficiently and remain long.

The object of the present invention is to overcome these drawbacks. This is accomplished by making the cylinder roll or cutter cylinder of a paper pulp mill provided 'with two pulp races Wider than the tail race leading from the cylinder and by arranging the cylinder so that its outer end stands or jutsq out beyond the outer edge of the tail race. At the outstanding part of the cylinder the pulp is thrown back over the top of the cylinder and led into a part of the race whence it is conducted to the head race. By this arrangement a much greater out-put is obtained through considerably increasing the width of the cylinder of the pulping machine. A thorough crosswise mixing of the pulp is effected, and as the Width of the cylinder is greater than that of the adjoining tail race no areas outside the pulp current are -formed where the pulp The width of the cylinder,`

stagnates and which spoil the quality of the milled pulp.

A constructional form of the invention is illustratedin the accompanying Figs. l'to 3 in which l Fig. 1 is a section on the line A-B of Fig. 2,

Fig. 2 is a top view in which the hood above the pulping cylinder is removed and Fig. 3 is a section of the paper pulpmachine on the line C-D of Fig. 2.

In the basin or tank a is journalled a grinding cylinder I; whose width isabout 1.2 of itsdiameter. The Width of the ridge c and of the part of the `tail race d adjoin ing the cylinder is about of that of cylinder or about 0.8 of its diameter. The cylinder is arranged in the tank so that the third of its width, by which it exceeds the width ot the tail race d, stands out. beyond the outer wall of the tail race. The wall e of the tank directly adjoins the outstanding part of the cylinder b. By arranging the cylinder t in this way'only of the 80 breadth ot' the pulp stream are conducted over the low ridge c into the tail race d which merges in the usual manner and width into the lateral returning race f. As the width of the race d amounts to 2/3 of vthat of the cylinder or to 0.8 of its diameter the normal, desirable slope or inclination of the race bottom is obtained at the outer wall of the races al and f. The remaining third of the Width of the pulp stream is thrown back over the top oit the outstanding part of the cylinder b into the race `at the front of the cylinder, this path ot the backwardly thrown pulp being determined by the closed hood g. The third of the pulp stream thus thrown to the front ot the cylinder t) goes into the channel L. which extends parallel to the cylinder axis. VThe channel h is formed or placed in the hood g and conducts the pulp down a slope through the middle wall of lthe tank or basin to the inner side of the race This returning race 'f widens out at the pointY where the pulp that is thrown back over the top of the cylinder is conducted into it. Therefore the cross-section of the returning race is suliicient to accommodate the two rccoml'iined pulp streams Without any congestion taking place. By the atoredescribed peculiar manner shown by arrows in Fig. 2) ot leading to the inner wall of the returning race f the part of the pulp stream that passes along the outer Wall of the tank, a very quick and eective crosswise mixing of the `pulp is accomplished.

Furthermore the lengths of travel of the fl different pulpistreams are perfectly equalized and the rate of theirA circulation increased, so that a grinding or pulping effect of the pulping machine 1s obtained which is much greater than in a machineof the ordinary design equipped with a cylinder of the same width butmuch larger diameter. As the outer wall e directly adjoins the part of the cylinder I) where the pulp is thrown back over the top ot the cylinder, no areas are formed beyond the rear of the cylinder which lie outside the pulp stream and inwhich a part of the pulp might sta ate. 4

o prevent losses through eddies in the part o the pulp stream that is thrown back over the cylinder, a smooth guide member z' of sheet metal is arranged to extend concentrically around the part of the cylinderb located in the upper part of the closed hood g. The sheet metal guide c' is attached at one end by a screw k or the like, located approximately in a horizontal plane through the middle ofthe cylinder, to the upper portion of the removable hood g. The other end of the guide z' is free so that it can ex freely to and fro above the top of the cylin der b. One or more screw-threaded spindles Z are riveted in the guide c' which have nuts m that rest against small supports n fixed to the hood g. By this means the exible sheet metal guide i can be held suspended at an desired adjustable distance above the perip ery of the cutter c linder. Surrounding the spindles Z are helical springs o whose one end abuts upon the top of the guide 71 and whose other end presses against the suprts n, so that the sheet metal guide i is eld at a certain distance from the cylinder against the centrifugal action of the pulp flung u therefrom. Furthermore the heli cal springs allow the sheet metal guide i to having ield in an upward direction in case the cyllnder should, for some reason or another,

y upwards.

I claim l. A pulpin machine com rising a tank having a hea race and a tail race formed therein, a `revolving pulpin cylinder that is wider than the tail race ending from it and arranged to stand out beyond the outer Wall of thetail race, and means for conducting material being pulpcd over the top of said outstanding part of the cylinder and in a direction 'parallel to the axis of the cylin der to the head race.

2. A pulping machine comprising a tank having a head race and a tail race formed therein, a revolving pulping cutter cylinder that is wider than the tail race leading from it and arranged to stand out beyond the outer Wall of the tail race. means for conducting material beingr pulped over the top of said outstanding part of the cutter cylinder and in a direction parallel to the axis of the cylinder to the head race. a hood above said cylinder, andan adjustable sheet metal guide member between said hood and the periph ery of said cylinder.

3. A pulping machine comprising a tank a head race, tail race and returningr race, which joins the tail race to the head race, formed therein, a revolving pulping cylinder that is Wider than the tail race leading from it and arranged to standout beyond the outer wall of the tail race, and means for conducting material being pulped over the top of said outstanding part of the cylinder and in a direction parallel to the axis of the cylinder into said returning race, the returning race being widened at the point where it receives pulp from said outstanding part of said cylinder as and for the purpose set forth.

In testimony whereof I have signed my name to this specification.

HERMANN MALLICKH.

er m 

